Improvement in the manufacture of metallic i-ngots and plates



H. MCDONALD.

MANUFACTUREYOF METALLIC INGOTS AND PLATES. N0.179,Z1Z. Patented June 27,1876.

N-PEIEHS. PHOTOLITHOGRAPHER, WASHINGTON. D C.

HUGH MCDONALD, OF ALLEGHENY, PENNSYLVANIA.

IMPROVEMENT IN THE MANUFACT'URE 0F METALLIC I-NGOTS AND PLATES.

Specification forming part of Letters Patent No. l 79,212, dated June 27, 1876; application filed October 12, 1875.

To all whom it may concern Be it known that I, HUGH McDoNALD, of Allegheny, in the county of Allegheny and State of Pennsylvania, have invented or discoved a new and useful Improvement in the Manufacture of Malleable Ingots and Plates; and I do hereby declare the following to be a full, clear, concise, and exact description thereof, reference being had to the accompanying drawing, making a part of this specilication, in which-like letters indicating like parts- Figure l is a perspective view of one form of ingot-mold illustrative of my improvement. Fig. 2 is a transv/erse vertical section of the same mold, with a portion of the ingot cast therein, and in place over a pit, for the removal of the core. Fig. 3 is a like view ofthe mold and complete ingot. Fig. et is a crosssection through the hollow part-ingot of Fig. 2, in the line a: w. Fig. 5 is a like sectional View through the complete ingot of Fig. 3 in the line m fr', and Fig. 6 is a perspective view of a hollow part-ingot, cast in two pieces, and ready for the casting ofthe central part.

In the manufacture of what is generally known as iron-center steel, it has been found difficult, from various causes, to secure a sufciently perfect weld or union between the dif- `ferent metals employed, and at the saine time a suiiiciently smooth, hard, unbroken exterior face. are liable to split apart, and lacking the latter element, they are almost wholly unsalable for many purposes for which they are manufactured. While it is not exactly certain how these defects arise, they seem to result from the mode of casting heretofore employed, the inner part of the ingot being made first, and the outer shell being afterward cast thereon. Gasses are apparently generated which, if the central slab be cold, destroy the perfectness of the weld, and which, in any case seem to form in globules on the exterior face of the outer casting, so as to leave a surface broken, porous, or pitted here and there, such as in the working of steel cannot be welded up.

My improvement is applicable to the manufacture of compound malleable metallic ingots and plates generally, but I design it especially for use in the productionk of ingots and plates wherein a malleable exterior steel Lacking the former element the metals face is desired along with a comparatively soft, tough center, and by the mode of manufacture which I employ, I am enabled to attain better results than have heretofore been found practicable. y

rIhe ingot-molds B B are made in the usual or any known way, except that at the bottom I make, by preference, a hole, b, of suitable size for receiving a central core, D. This core is inserted in the mold in the manner illustrated in Figs. 1 and 2, and its lower end is placed directly over a hole, b', in the floor, which leads into a pit, D. The central core D is preferably made slightly tapering, for greater facility in removing it at the proper time, also hollow, in order that by a jet of water or other uid, liquid or gaseous, sprayed, injected, or supplied inside of it, its temperature may be regulated. But I do not consider these features as absolutely essential. The core D being properly centered, the molten steel which is to form the hard exterior is poured into the cavity or space between the core and the inner walls of the mold, so as to form the hollow part-ingot P. As soon as it shall have set sufficiently to stand, and, preferably, before it shall be fully solidified, I force the central core D out by a sharp blow, or by pressure from above, so as to drop it into the pit, and then, as soon as the mold and part-ingot can be shifted from over the pit D', or the lower ingot-opening b can be stopped up, I turn into the hollow of the part-ingot P such other quality or kind of softer or tougher malleable metal as may be desired to form the center P of the complete iugot. The opening b may be filled by a tongue projecting up from the floor below, or by some sand thrown in from above before the central cast.- The subsequent manipulation aud treatment of the compound iugot by rolling or hammering, so as to bring it to a sheet or plate form, are such as is already known in the art.

By thus casting the two malleable metals together, one above and the other but a little below the fusing-point, I so fuse or partly fuse the interior face of the latter as to secure in the rolled or hammered plates a more perfect union of the two metals than has yet been attained, and also by casting the exterior part first, of the best metal and under the most favorable conditions, I secure the best attainable perfectness of exterior surfaces, in the finished or rolled or hammered product.

The use of the same improvement is illustrated in a modified form in Fig. 6, where P2 P2 represent each one-half of the part-ingot P above described. These halves may be cast separately, each of a U shape, and as quickly as possible after properly setting77 they are brought together and banded, or otherwise secured, and the soft center cast into the hollow p, as before described. I consider this a practicable, though a less perfect, way of attaining the desired result.

The different qualities or kinds of malleable metal to be used in the exterior and interior parts of the ingot, may be varied according to the product or kind or quality or requirements of the product desired. Any combination of such metals, or of difterent-qualities of the same metal, which, in the operation of casting one within another, will give an ingot slab or plate with a fused or welded union of one to the other and both malleable, may be made within the present improvement. Nor

is'itnecessary that in casting the exterior part the metal should flow around on all sides of the core. The exterior part P of the ingot may be cast in two slabs or plates, and on the removal of the core the central part P-l may be cast between them.

l am aware that the compounding` of nonmalleable cast metal, by casting 'a cast-iron body within a previously-cast cast-iron shell, is not new, but such a product is in no sense of the term aningot. It is incapable of being further worked by rolling or hammering, nor is any useful result attained thereby, other than giving a hard-metal cast surface-to the article cast. In the ingot which I make, not only is a hard surface required, but also one which, while retaining its hardness, may, by rolling or hammering, receive and retain a high perfect finish. I also deem it important that the two metals, or the two qualities of metals, be united while both are at a high heat, which element is not material in roll casting. Also the union thus effected must besuch as Will not be seriously, if at all, impaired by the changes which the compounded product undergoes while beingrolled, hammered, or swaged. l

I make no claim herein as regards nonmalleable metals, nor as regards ingots which are non-malleable. Nor do I make any claim to anything shown or described iu the patents of Park, No. 78,47 7, and Doyle, No. 99,299.

Iclaim as my inventionp l. As an improvement in the art of making compound malleable plates, casting the softer quality of malleable metal Within or between the previously cast and yet hot exterior malleable plates of a harder quality, substantially as set forth.

2. As an improvement in the art of making compound malleable plates, the process consisting ofthe following steps: first, casting the exterior or surface part or parts ofthe harder quality of malleable metal; second, castingv therein While still hot the interior core or center of a softer quality of malleable metal; and, third, bringing the same to a sheet or plate form by known operations of hammering or rolling, substantially in the manner and for the purposes set forth.

In testimony whereof I have hereunto set my hand.

HUGH MCD oNALD.

Witnesses:

J AMES BLACK, GEORGE H. CHRISTY. 

